The present invention relates to multiple-jaw chucks, such as those used to clamp a workpiece during a machining operation.
A popular type of multiple-jaw chuck widely used today comprises a housing and a drive cylinder pneumatically driven parallel to the longitudinal axis of the housing and coupled to a plurality of chuck jaws to drive them radially towards and away from the housing longitudinal axis in order to clamp or disengage the workpiece. This popular type of chuck includes a rib-and-slot coupling of T-configuration between the drive cylinder and each of the chuck jaws, and a further rib-and-slot guide also of T-configuration to guide the movement of the chuck jaws while they are driven by the cylinder. Such known constructions, however, have a number of disadvantages. Thus, forming the T-configuration for the rib-and-slot coupling and for the guide involves high-precision, time-consuming machine operations which increase the manufacturing cost of the chuck. Moreover, with such T-configuration metal-to-metal contact faces, it is very difficult, no matter how high the precision, to preclude the entry of dirt between the metal faces particularly at the sharp corners, which dirt increase the wear on the parts and shortens their useful life.